1. Technical Field
Illustrative embodiments described in this patent specification generally relate to a sheet discharger and an image forming apparatus including the sheet discharger.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, printers, facsimile machines, and multifunction devices having two or more of copying, printing, and facsimile functions, typically form a toner image on a recording medium (e.g., a sheet of paper) according to image data using an electrophotographic method. In such a method, for example, a charger charges a surface of an image carrier (e.g., a photoconductor); an irradiating device emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor; a transfer device transfers the toner image formed on the photoconductor onto a sheet; and a fixing device applies heat and pressure to the sheet bearing the toner image to fix the toner image onto the sheet. The sheet bearing the fixed toner image is then discharged from the image forming apparatus by a sheet discharger.
Related-art sheet dischargers often employ a catch system, in which a rear edge of a sheet being discharged from the image forming apparatus is sandwiched by a pair of discharge rollers to hold the sheet while the rest of the sheet hangs exposed from the image forming apparatus.
In such sheet dischargers, the sheet thus sandwiched by the pair of discharge rollers is pulled by a user to be discharged from the image forming apparatus. At this time, the discharge rollers, which are in a stopped state to sandwich the sheet, are rotated by the pulling of the sheet. However, because the pair of discharge rollers is connected to a driving unit such as a motor, a load torque is generated by rotating the pair of discharge rollers in this stopped state. Consequently, a certain amount of force is required for the user to pull the sheet out of the image forming apparatus, causing inconvenience to the user to discharge the sheet from the image forming apparatus.
In addition, the sheet pulled by the user scrapes against the pair of discharge rollers, possibly causing toner or dust attached to the pair of discharge rollers to be further attached to the sheet. Further, an image formed near the rear edge of the sheet may be damaged by such scraping against the pair of discharge rollers.
A lever is sometimes provided to separate the pair of discharge rollers from each other to release the sheet when the sheet is pulled out of the image forming apparatus, thereby solving the above-described problems and inconvenience. However, because the user must operate the lever before pulling the sheet out of the image forming apparatus, an additional operation is imposed on the user to discharge the sheet from the image forming apparatus.